Copter 4.5.7 – Proximity sensor detected (PRX logged) but vehicle does not stop in Loiter (worked in 4.5.6)

ArduCopter Copter 4.5
1

Hi all,

We are observing a behavior change after upgrading firmware from ArduCopter 4.5.6 to 4.5.7.

**
Hardware**

  • Flight Controller: Cube Orange+

  • Vehicle: Quad Copter

  • Obstacle sensor: Rangefinder (forward facing)

  • Backend: PRX1_TYPE = 4 (RangeFinder → Proximity conversion)

  • Data rate: ~10–20 Hz

What works

From DataFlash log / UAV Log Viewer:

  • RFND data present

  • PRX sectors populated

  • Obstacle distances correctly detected

  • Distance drops to ~0.3–0.5 m

  • Tested in LOITER mode

So the autopilot is clearly detecting obstacles and generating a proximity map.

What does NOT work

The vehicle does NOT slow or stop when flying toward the obstacle using stick input.

Observed behavior:

  • Copter continues moving forward

  • No velocity limiting or braking

  • No avoidance reaction

Important observation

The exact same parameters and hardware worked correctly in Copter 4.5.6.
After upgrading to 4.5.7, stopping behavior disappeared.

So this appears to be a behavior/logic change rather than a sensor configuration issue.

Parameters
AVOID_ENABLE = 2
OA_TYPE = 0 (also tested 1)
AVOID_BEHAVE = 1
PRX1_TYPE = 4
PSC_POSXY_P = 0.5

Logs

Logs show valid proximity data:

  • PRX sectors populated

  • Obstacle distance < 0.5 m

  • Mode = LOITER

Yet no braking occurs.

Question

Was there a change in Copter 4.5.7 regarding proximity-based manual stick braking in Loiter mode?

Why does the vehicle not stop even though PRX data is valid and obstacle distance is well below the avoidance margin?

Is there an additional parameter required in 4.5.7 to re-enable proximity-based velocity limiting?

Thanks in advance…!!!

2

Hi all,

We performed additional testing to verify whether this is strictly a 4.5.7 regression.

After observing the issue, we downgraded the firmware back to ArduCopter 4.5.6 and tested again using the same hardware and the exact same parameter set.

However, the vehicle still does not stop or slide in Loiter when approaching the obstacle.
The behavior is identical to what we observed in 4.5.7:

  • RFND data present

  • PRX sectors populated

  • Obstacle distance decreases to < 0.5 m

  • Mode = LOITER

  • Yet no braking or velocity limiting occurs

So it now appears the issue is not purely version-dependent and may be related to configuration, interaction with another controller parameter, or a change that persists across firmware loads.

I will attach the corresponding .bin log from this test for review.

We used the same parameters as mentioned earlier.

Please let me know if any specific log messages or parameters should be checked.

Thanks.

log.bin